Slide rule



T. M. OSLER July 27, 1965 SLIDE RULE Filed July 24, 1965 5 ww m m wo @7m M. R O E w N Q w TW N/ w Wm United States Patent O 3,197,135 SLIDE RULE Turner M. Osier, 5007 N. 36th St., Arlington, Va. )Filed July 24, 1963, Ser. No. 297,392 4 Claims. (Cl. 23S-70) This invention relates to improvements in computing slide rules and more particularly to a novel device suitable for performing additions and subtractions of positive or negative numbers.

Previous slide rules have been devised to perform additions and subtractions. However, these rules have been limited to the use of positive numbers. The present slide rule allows for the addition and subtraction of positive and negative numbers or a combination of positive and negative numbers. A primary object of the present invention is to provide a slide rule for performing addition and subtraction operations with both positive and negative integers.

Another object is to provide a device of the above type which has a triangular cross-section.

A further object is to provide a device of the above type which is characterized by improved construction that will enable the rule to be made inexpensively, rapidly and reliably.

Various other objects and advantages of the invention will be apparent during the course of the following description.

In the accompanying drawings, in which like numerals designate like parts, FIGURE l is a top plan view;

FIGURE 2 is a side elevation;

FIGURE 3 is a transverse section view of the rule taken along line 3-3 of FIGURE 2.

The slide rule is comprised of a base, generally shown as 20, which is shaped to form a channel 28, and a slide, generally shown as 21, which is held by channel 28 and is slidable within this channel.

The base 20, which can be conveniently made from one piece of material, is composed of a ilat bottom section 22 and two side sections 24 bent or molded so that the side sections form angles of approximately 60 with respect to the bottom section 22. The base 20 could also be formed of separate bottom and side pieces which are suitably joined together. The outer faces of both of the side sections 24 are provided with scales 26, each scale being divided into a set of equal spaces. Each division of the scales 26 carries a number, starting at 0 in the center of the scale and progressing arithmetically to the right and to the left of center. The numbers to the right of center on both scales 26 are positive and those to the left of center are negative.

The slide 21, which moves in channel 28 formed by bottom section 22 and upstanding side section 24, can conveniently be made from one piece of material bent or molded in the shape of an inverted v The slide 21 could also be made of separate members properly joined together. The two side members 23 and 25 of the slide 21 form an acute angle of approximately 60. The outer faces of members 23 and 25 of slide 21 are provided with scales 27 and 29, respectively. Scales 27 and 29 are divided into equal spaces, each division carrying a number. The numbers start at in the center of each scale and progress arithmetrically to the right and to the left of center. On scale 27, the numbers to the right of center are positive and those to the left are negative. On scale 29, the numbers to the right of center :are negative and those to the left are positive.

All four scales are divided equally and are centered such that when all four zeroes are in alignment, all other numbers are similarly aligned. For ease of distinction, the scales could each have numerals of diiferent type, for

3,197,135 Patented July 27, 1965 example small and large or straight and slanted numerals. The various scales could also be distinguished by colors and thus facilitate addition or subtraction.

For addition, with the rule assembled as shown in the figures, the 0 of scale 27 is slid until it is directly over one of the addends on scale 26. The second addend is found on scale 27 and the sum is read on scale 26 directly below the second addend. As shown in FIGURE 2, the O on scale 27 appears above 6 on scale 26 and under 8 on scale 27 appears the sum 14 on scale 26. The procedure is exactly the same when adding a positive and negative number. Referring again to FIGURE 2, with the O over the 6 the negative 8 is found on the left side of scale 27 and directly below on scale 26 is the sum, negative 2. Also two negative numbers may be added using the same procedure. A series of numbers can be added in this manner to.

For subtraction, the 0 on scale 29 is slide until it is over the minuend on scale 26. Now the subtrahend is found on scale 29 and directly below on scale 26 is the difference or remainder. Two positive numbers, two negative numbers or positive and a negative number can be subtracted. In FIGURE l the 0 of scale 29 is over negative 6 on scale 26, now subtracting positive 8 on scale 29, the difference is read directly below the 8 of scale 29. The difference of negative 6 and positive 8 is negative 14 as read on scale 26.

Preferably the numbers on scale 27 and one of the scales 26 are given a distinctive color, such as red, to distinguish these addition scales from scale 29 and the remaining scale 26 which are used for subtraction and may be black. This allows the user to recognize at a glance the addition and subtraction scales.

The ability to add and subtract negative as well as positive numbers greatly increases the utility of this type of slide rule.

The unique design of this rule also adds to its utility. This rule has its scales positioned such that they are readily visible when the rule is sitting on its base. This is not the case with liat rules which must be picked up t0 be read. The present rule would be especially useful to persons sitting at a desk. A convenient arrangement would be to have the rule loosely fastened to a desk top by a screw through a hole in the center of the base. This arrangement would allow the rule to be turned for addition or subtraction and yet would hold the base in place for easy one hand operation.

Although a preferred embodiment has been shown as an illustration, it is to be understood that variations may be made therein and the invention may be applied to other uses as readily apparent t0 one skilled in the art. The invention is limited only in accordance with the scope of the following claims.

What I claim is:

1. A slide rule comprising a base having a ilat bottom section and two side pieces,

said side pieces extending angularly from said bottom section toward one another, said pieces each forming an acute inner angle with said bottom section, said side pieces extending from said bottom section a distance of approximately one-half of the width of said bottom section such that said side pieces and said bottom section form an open longitudinal guideway,

rand a slide having two side members in the form of an inverted V,

said slide fitting movable into said guideway,

said guideway allowing longitudinal movement of said slide and said guideway preventing lateral movement of said slide.

2. A slide rule as in claim 1 having scales located on the two outer faces of the side pieces of the base,

said scales being divided into equal spaces and each division carrying a number,

said numbers starting at zero in the center of each scale and progressing arithmetically to the right and to the left of center,

those numbers to the right of center on both scales being positive and those to the left being negative.

3. A slide rule as in claim 2 having scales located on the outer faces of the slide,

said scales being divided into equal spaces and each division carrying a number,

said numbers starting at zero in the center of each scale and progressing arithmetically to the right and to the left of center,

one of said scales having the number to the right of center positive and those to the left negative, and

the other scale having those numbers to the left of center positive and those to the right negative.

4. A slide rule comprising a base having a flat bottom section and two side pieces,

said side pieces extending angularly from said bottom section a distance of approximately one-half of the width of said bottom section,

said pieces each forming an acute inner angle with said bottom section,

said side pieces and said bottom section forming a three sided unclosed longitudinal guideway;

and a slide having two side members in the form of an inverted V,

said slide fitting moveably into said guideway,

said guideway allowing longitudinal movement of said slide and said guideway preventing lateral movement of said slide;

the outer faces of said side pieces and said side mem bers of the base and the slide, respectively, having numerical indicia for use in mathematical calculations.

References Cited by the Examiner UNITED STATES PATENTS 603,695 5/98 Keuel 23S- 70 648,576 5/00 Taylor. 2,569,202 9/51 Solomon 23S- 70 LEO SMILOW, Primary Examiner. 

1. A SLIDE RULE COMPRISING A BASE HAVING A FLAT BOTTOM SECTION AND TWO SIDE PIECES, SAID SIDE PIECES EXTENDING ANGULARLY FROM SAID BOTTOM SECTION TOWARD ONE ANOTHER, SAID PIECES EACH FORMING AN ACUTE INNER ANGLE WITH SAID BOTTOM SECTION, SAID SIDE PIECES EXTENDING FROM SAID BOTTOM SECTION A DISTANCE OF APPROXIMATELY ONE-HALF OF THE WIDTH OF SAID BOTTOM SECTION SUCH THAT SAID SIDE PIECES AND SAID BOTTOM SECTION FORM AN OPEN LONGITUDINAL GUIDEWAY, AND A SLIDE HAVING TWO SIDE MEMBERS IN THE FORM OF AN INVERTED "V", SAID SLIDE FITTING MOVABLE INTO SAID GUIDEWAY, SAID GUIDEWAY ALLOWING LONGITUDINAL MOVEMENT OF SAID SLIDE AND SAID GUIDEWAY PREVENTING LATERAL MOVEMENT OF SAID SLIDE. 